Integrated circuit (AC) chips using complementary metal-oxide-semiconductor (CMOS) technology have advantages when compared to those using emitter-coupled logic (ECL) technology. Among the advantages are lower power consumption and hence lower cooling requirements, and lower construction cost. However, CMOS chips are inferior to ECL chips in both intra-chip and inter-chip (backpanel) operation speeds. The aforementioned advantages of ECL chips are mainly due to a lower voltage swing between logic low and logic high levels (-1.7 to -0.9 volts for ECL, 0 to 5 volts for CMOS), and fewer transmission line effects resulting from impedance matching.
Prior art CMOS data transfer systems exist for intra-chip communication which limit data bus swings to ECL levels, and employ CMOS-to-ECL converters, and vice versa. What is desired is a CMOS inter-chip data transfer system which not only limits voltage swings to increase data transfer speed, but which is also operable at logic levels other than the standard ECL levels (but falling between the CMOS levels), according to design choice.